Measure growth of plant cell culture - (Jan/15/2014 )

Hi all, I'm working on my apple suspension culture and need to measure the growth, but I'm struggling to get the best and simple method to measure the growth. Currently what I do is measure the fresh weight but it seems not accurate as I still got the water left on the filter paper after the vacuuming process. Can I know how you guys measure your suspension culture growth?...thanks for your help...

Couldn't you just take an aliquot and count cells?